1. Field of the Invention
The present invention relates generally to fluid flow control mechanisms. More particularly the invention relates to a fluid flow injection control mechanism for use with Tesla-type turbines where it is desired to control the mass flow of the fluid to the turbine without changing the fluid injection angle and without introducing turbulence.
2. Discussion of the Prior Art
Tesla-type, bladeless turbines present many advantages in cases where the power fluid contains large amounts of impurities, such as is the case of geothermal water or the product of the gasification of coal. However, heretofore this type of turbine has not been extensively used primarily because of problems with the fluid injection mechanisms available for use with the turbines.
Existing fluid injecting mechanisms suitable for use with Tesla-type turbines are either fixed or movable by rotation. In the case of fixed mechanisms, the fluid is injected at a constant angle but no control is provided. Accordingly, in such mechanisms any required modulation of the mass flow, such as is needed to meet the demands of a variable load, must be met by means of a throttling valve located upstream of the injection mechanism. The use of a throttling valve, however, invariably results in a loss of efficiency, severe turbulence in the fluid and the possibility of vapor flashing and liquid slugging.
In the case of rotatable mechanisms, control is typically achieved by rotating a plurality of shaped elements which vary the area open to the flow between them. These types of devices tend to obviate some of the difficulties inherent in fixed type mechanisms, but at the cost of a change in injection angle and flow geometry which invariably results in a substantial decrease in operating efficiency.
The present invention concerns a unique mechanism for controllably injecting variable amounts of fluid into a Tesla-type bladeless turbine without any changes in injection angle or in fluid flow geometry.
As will become apparent from the discussion which follows, the apparatus of the present invention effectively overcomes the drawbacks of the prior art fluid injection mechanisms and for the first time provides a viable fluid flow control mechanism for use with Tesla-type turbines.
Applicant is familiar with the patents issued to J. S. Swearingen, U.S. Pat. Nos. 3,495,921 and 3,232,581, which patents represent the most pertinent art known to applicant and which serve to clearly illustrate the novelty of the present invention.